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  1. Article ; Online: Superionic effect and anisotropic texture in Earth’s inner core driven by geomagnetic field

    Shichuan Sun / Yu He / Junyi Yang / Yufeng Lin / Jinfeng Li / Duck Young Kim / Heping Li / Ho-kwang Mao

    Nature Communications, Vol 14, Iss 1, Pp 1-

    2023  Volume 8

    Abstract: Earth’s inner core is heterogeneous and anisotropic. A new study based on computational simulation reveals the presence of ionic hydrogen flux in iron crystals, driven by the dipole geomagnetic field, which promotes the formation of observed inner core ... ...

    Abstract Earth’s inner core is heterogeneous and anisotropic. A new study based on computational simulation reveals the presence of ionic hydrogen flux in iron crystals, driven by the dipole geomagnetic field, which promotes the formation of observed inner core structure.
    Keywords Science ; Q
    Language English
    Publishing date 2023-03-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Measurement of ferric iron in Chang’e-5 impact glass beads

    Lixin Gu / Yangting Lin / Yongjin Chen / Yuchen Xu / Xu Tang / Sen Hu / Ho-kwang Mao / Jinhua Li

    Earth, Planets and Space, Vol 75, Iss 1, Pp 1-

    2023  Volume 10

    Abstract: Abstract The lunar surface and interior are highly reducing, resulting in the virtually absence of ferric ion. However, recent studies suggest the presence of ferric iron in lunar samples, and in most cases they were found in amorphous silicates (e.g., ... ...

    Abstract Abstract The lunar surface and interior are highly reducing, resulting in the virtually absence of ferric ion. However, recent studies suggest the presence of ferric iron in lunar samples, and in most cases they were found in amorphous silicates (e.g., glass beads) measured by TEM–EELS. In this work, we conducted a systematic TEM–EELS analysis on the iron valence states of Chang’e-5 impact glass beads. The Fe3+/ΣFe ratio of each silicate glass sample was determined from integral intensity of Fe L3 and L2 edge. The measurements show a positive correlation between the dwell time and Fe3+/ΣFe ratio, which reveals that ferric iron can be significantly produced by electron beam bombardment under routine analytical condition. The calculated Fe3+/ΣFe with short dwell times (≤ 20 ms) in our Chang’e-5 impact glass beads show no detectable inherent ferric iron, suggesting that the ferric iron is not ubiquitous as previously reported. It is obvious that a careful control of experiment conditions is critical to determine the inherent redox state of other beam-sensitive terrestrial and extraterrestrial samples. Graphical Abstract
    Keywords Lunar soils ; Chang’e-5 ; Ferric iron ; EELS ; Beam damage ; Geography. Anthropology. Recreation ; G ; Geodesy ; QB275-343 ; Geology ; QE1-996.5
    Language English
    Publishing date 2023-10-01T00:00:00Z
    Publisher SpringerOpen
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Coupled deep-mantle carbon-water cycle

    Wenzhong Wang / Oliver Tschauner / Shichun Huang / Zhongqing Wu / Yufei Meng / Hans Bechtel / Ho-Kwang Mao

    The Innovation, Vol 2, Iss 2, Pp 100117- (2021)

    Evidence from lower-mantle diamonds

    2021  

    Abstract: Diamonds form in a variety of environments between subducted crust, lithospheric and deep mantle. Recently, deep source diamonds with inclusions of the high-pressure H2O-phase ice-VII were discovered. By correlating the pressures of ice-VII inclusions ... ...

    Abstract Diamonds form in a variety of environments between subducted crust, lithospheric and deep mantle. Recently, deep source diamonds with inclusions of the high-pressure H2O-phase ice-VII were discovered. By correlating the pressures of ice-VII inclusions with those of other high-pressure inclusions, we assess quantitatively the pressures and temperatures of their entrapment. We show that the ice-VII-bearing diamonds formed at depths down to 800 ± 60 km but at temperatures 200–500 K below average mantle temperature that match the pressure-temperature conditions of decomposing dense hydrous mantle silicates. Our work presents strong evidence for coupled recycling of water and carbon in the deep mantle based on natural samples.
    Keywords diamond ; deep mantle ; water and carbon cycle ; first-principles calculations ; Science (General) ; Q1-390
    Language English
    Publishing date 2021-05-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Nested order-disorder framework containing a crystalline matrix with self-filled amorphous-like innards

    Kejun Bu / Qingyang Hu / Xiaohuan Qi / Dong Wang / Songhao Guo / Hui Luo / Tianquan Lin / Xiaofeng Guo / Qiaoshi Zeng / Yang Ding / Fuqiang Huang / Wenge Yang / Ho-Kwang Mao / Xujie Lü

    Nature Communications, Vol 13, Iss 1, Pp 1-

    2022  Volume 9

    Abstract: The synthesis and characterization of new crystalline-amorphous hybrid materials is challenging. Here, the authors report the preparation of a nested order-disorder framework by applying high pressure to a nested copper chalcogenide Cu12Sb4S13. ...

    Abstract The synthesis and characterization of new crystalline-amorphous hybrid materials is challenging. Here, the authors report the preparation of a nested order-disorder framework by applying high pressure to a nested copper chalcogenide Cu12Sb4S13.
    Keywords Science ; Q
    Language English
    Publishing date 2022-08-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Temperature-induced amorphization in CaCO3 at high pressure and implications for recycled CaCO3 in subduction zones

    Mingqiang Hou / Qian Zhang / Renbiao Tao / Hong Liu / Yoshio Kono / Ho-kwang Mao / Wenge Yang / Bin Chen / Yingwei Fei

    Nature Communications, Vol 10, Iss 1, Pp 1-

    2019  Volume 8

    Abstract: Subduction of oceanic crust introduces huge amounts of carbonates into Earth’s mantle, contributing to the global carbon cycle. Here, based on high-pressure-temperature experiments, the authors present a reversible temperature-induced transition from ... ...

    Abstract Subduction of oceanic crust introduces huge amounts of carbonates into Earth’s mantle, contributing to the global carbon cycle. Here, based on high-pressure-temperature experiments, the authors present a reversible temperature-induced transition from aragonite to amorphous CaCO3.
    Keywords Science ; Q
    Language English
    Publishing date 2019-04-01T00:00:00Z
    Publisher Nature Publishing Group
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Temperature-induced amorphization in CaCO3 at high pressure and implications for recycled CaCO3 in subduction zones

    Mingqiang Hou / Qian Zhang / Renbiao Tao / Hong Liu / Yoshio Kono / Ho-kwang Mao / Wenge Yang / Bin Chen / Yingwei Fei

    Nature Communications, Vol 10, Iss 1, Pp 1-

    2019  Volume 8

    Abstract: Subduction of oceanic crust introduces huge amounts of carbonates into Earth’s mantle, contributing to the global carbon cycle. Here, based on high-pressure-temperature experiments, the authors present a reversible temperature-induced transition from ... ...

    Abstract Subduction of oceanic crust introduces huge amounts of carbonates into Earth’s mantle, contributing to the global carbon cycle. Here, based on high-pressure-temperature experiments, the authors present a reversible temperature-induced transition from aragonite to amorphous CaCO3.
    Keywords Science ; Q
    Language English
    Publishing date 2019-04-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: The stability of subducted glaucophane with the Earth’s secular cooling

    Yoonah Bang / Huijeong Hwang / Taehyun Kim / Hyunchae Cynn / Yong Park / Haemyeong Jung / Changyong Park / Dmitry Popov / Vitali B. Prakapenka / Lin Wang / Hanns-Peter Liermann / Tetsuo Irifune / Ho-Kwang Mao / Yongjae Lee

    Nature Communications, Vol 12, Iss 1, Pp 1-

    2021  Volume 7

    Abstract: Along the cold subduction geotherm, glaucophane remains stable down to pressure and temperature (P–T) conditions of ca. 240 km depth, whereas under the warm subduction geotherm, it dehydrates and breaks down into pyroxenes and silica between ca. 50 and ... ...

    Abstract Along the cold subduction geotherm, glaucophane remains stable down to pressure and temperature (P–T) conditions of ca. 240 km depth, whereas under the warm subduction geotherm, it dehydrates and breaks down into pyroxenes and silica between ca. 50 and 100 km depths.
    Keywords Science ; Q
    Language English
    Publishing date 2021-03-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article: Pressure-Driven Reversible Switching between n- and p-Type Conduction in Chalcopyrite CuFeS₂

    Wen, Ting / Yonggang Wang / Nana Li / Qian Zhang / Yongsheng Zhao / Wenge Yang / Yusheng Zhao / Ho-kwang Mao

    Journal of the American Chemical Society. 2018 Nov. 28, v. 141, no. 1

    2018  

    Abstract: Temperature-dependent switching between p- and n-type conduction is a newly observed phenomenon in very few Ag-based semiconductors, which may promote fascinating applications in modern electronics. Pressure, as an efficient external stimulus that has ... ...

    Abstract Temperature-dependent switching between p- and n-type conduction is a newly observed phenomenon in very few Ag-based semiconductors, which may promote fascinating applications in modern electronics. Pressure, as an efficient external stimulus that has driven collective phenomena such as spin-crossover and Mott transition, is also expected to initialize a conduction-type switching in transition metal-based semiconductors. Herein, we report the observation of a pressure-driven dramatic switching between p- and n-type conduction in chalcopyrite CuFeS₂ associated with a structural phase transition. Under compression around 8 GPa, CuFeS₂ undergoes a phase transition with symmetry breakdown from space group I-42d to space group I-4 accompanying with a remarkable volume shrinkage of the FeS₄ tetrahedra. A high-to-low spin-crossover of Fe²⁺ (S = 2 to S = 0) is manifested along with this phase transition. Instead of pressure-driven metallization, a surprising semiconductor-to-semiconductor transition is observed associated with the structural and electronic transformations. Significantly, both photocurrent and Hall coefficient measurements confirm that CuFeS₂ undergoes a reversible pressure-driven p–n conduction type switching accompanying with the structural phase transition. The absence of cationic charge transfer between copper and iron during the phase transition is confirmed by both X-ray absorption near-edge spectra (Cu/Fe, K-edge) and total-fluorescence-yield X-ray absorption spectra (Fe, K-edge) results, and the valence distribution maintains Cu²⁺Fe²⁺S₂ in the high-pressure phase. The observation of an abrupt pressure-driven p–n conduction type switching in a transition metal-based semiconductor paves the way to novel pressure-responsive switching devices.
    Keywords X-ray absorption spectroscopy ; copper ; electric current ; electronics ; geometry ; iron ; phase transition ; semiconductors ; shrinkage
    Language English
    Dates of publication 2018-1128
    Size p. 505-510.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 3155-0
    ISSN 1520-5126 ; 0002-7863
    ISSN (online) 1520-5126
    ISSN 0002-7863
    DOI 10.1021/jacs.8b11269
    Database NAL-Catalogue (AGRICOLA)

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  9. Article ; Online: Pressure-stabilized divalent ozonide CaO3 and its impact on Earth’s oxygen cycles

    Yanchao Wang / Meiling Xu / Liuxiang Yang / Bingmin Yan / Qin Qin / Xuecheng Shao / Yunwei Zhang / Dajian Huang / Xiaohuan Lin / Jian Lv / Dongzhou Zhang / Huiyang Gou / Ho-kwang Mao / Changfeng Chen / Yanming Ma

    Nature Communications, Vol 11, Iss 1, Pp 1-

    2020  Volume 7

    Abstract: Calcium and oxygen are abundant elements in the Earth’s mantle, largely present as calcium oxide. Here the authors show, by experiments and computations, that calcium ozonide (CaO3) is stabilized at the high pressures and temperatures characteristic of ... ...

    Abstract Calcium and oxygen are abundant elements in the Earth’s mantle, largely present as calcium oxide. Here the authors show, by experiments and computations, that calcium ozonide (CaO3) is stabilized at the high pressures and temperatures characteristic of the lower mantle, with implications for the deep Earth’s chemistry.
    Keywords Science ; Q
    Language English
    Publishing date 2020-09-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Altered chemistry of oxygen and iron under deep Earth conditions

    Jin Liu / Qingyang Hu / Wenli Bi / Liuxiang Yang / Yuming Xiao / Paul Chow / Yue Meng / Vitali B. Prakapenka / Ho-Kwang Mao / Wendy L. Mao

    Nature Communications, Vol 10, Iss 1, Pp 1-

    2019  Volume 8

    Abstract: Iron oxides prevail in the deep Earth, at extreme pressures and temperatures, with different stoichiometries than in ambient conditions. Here, high-pressure synchrotron X-ray spectroscopic measurements reveal the oxidation states of Fe and O in iron ... ...

    Abstract Iron oxides prevail in the deep Earth, at extreme pressures and temperatures, with different stoichiometries than in ambient conditions. Here, high-pressure synchrotron X-ray spectroscopic measurements reveal the oxidation states of Fe and O in iron superoxide, shedding light on the puzzling chemistry of iron and oxygen in the deep Earth
    Keywords Science ; Q
    Language English
    Publishing date 2019-01-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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